start cap bleed resistors

[dfelt]

I,ve got two rural locations [bible camps actually]w/w.i.coolers,freezers,r.i.beverage coolers and other smaller refrig.equipment.I know the power is not great because of wind storms causing spikes/whathaveyou.At the one location this spring I installed metal oxide varistors on individual equip.and seams to be protecting compressor electrics where before they would fry in a storm.Owner declined to do anything more costly and utility co.won,t help either.
At the other place start capacitors want to die frequently[measured voltages are good while there]I,ve read Copeland literature that says they want to see replacement start caps installed w/15-18kohm bleed resistors esp.if equipment is subject to short cycling due to a cple.of things.Question is :jobber start caps a lot of times don,t c/w.Should I be soldering them in?The relays are sometimes failed.Is this because start cap is discharging yet as unit starts again?

[Phase Loss]

:tha,t is the -Purpose o f the Resis,tor's.

[mspanky]

I,ve got two rural locations [bible camps actually]w/w.i.coolers,freezers,r.i.beverage coolers and other smaller refrig.equipment.I know the power is not great because of wind storms causing spikes/whathaveyou.At the one location this spring I installed metal oxide varistors on individual equip.and seams to be protecting compressor electrics where before they would fry in a storm.Owner declined to do anything more costly and utility co.won,t help either.
At the other place start capacitors want to die frequently[measured voltages are good while there]I,ve read Copeland literature that says they want to see replacement start caps installed w/15-18kohm bleed resistors esp.if equipment is subject to short cycling due to a cple.of things.Question is :jobber start caps a lot of times don,t c/w.Should I be soldering them in?The relays are sometimes failed.Is this because start cap is discharging yet as unit starts again?

You can use crimp connectors to hold the resistors, and yes they are there to protect the start relay from arcing.

[rocket]

a potential relay is normally closed, if on shut down, any voltage is in the start cap, it will discharge across the relay points, eventually burning them out. That's why they are REQUIRED by Copeland and Tecumseh on any compressor using a potential relay!.

[Octopus]

Do you know how many hits Metal oxide varistor's are good for? One good hit and they are done they work but it's a one time deal.

[uniservice]

Get a baggie of 10 @ Johnstone with the terminals already on em G32-082

[INTECHBILL]

An aftermarket adjustable potential relay would work great for your problem.

[wannafreeze]

I always install start capacitors with resistors. I don't solder them, don't even need to use spade connectors (have done that too); just put the leads through the holes on the capacitor terminals and twist them nicely with your needlenose. It will do the job.

[VTP99]

I always thought the resistors were to minimize the arc when the contacts open the start winding.

[Phase Loss]

its to eliminate the arc when the relay resets to its N.C position.

The resistor bleeds start cap charge so it will not discharge through the start winding when the compressor comes to a stop. If this is allowed to happen, the contacts will arc. And in time..will weld closed.

[VTP99]

So its not to bleed the charge during the off cycle?

[Phase Loss]

nope, its to bleed the charge during the on cycle.

[VTP99]

Refrigeration & Air Conditioning Technology 5th Edition must have it wrong read Unit 20.11

[Phase Loss]

yup, sure enough. Page 375 in red ink under safety precaution.

But look at a wiring diagram and think about how a potential relay works AND you will understand that book is wrong.

[icemeister]

The book would be correct if it were a current relay and not a potential relay.

The current relay contacts are normally open, so you would get the capacitor discharging on shutdown, or during the off-cycle.

A potential relay's contacts are normally closed, so the arcing would occur when the contacts open on startup, or during the on-cycle.

[VTP99]

Icemeister is my #9 post wrong ( open the start winding or open on startup as you say ) ?

[VTP99]

Phase Loss i was refering to off-cycle of the relay. My bad because most techs think in terms of compressor cycle. Is off-cycle of the relay even right. Now that i'm thinking about it that should be on not off because when the points are open the relay is on due to EMF or is it CEMF ? Now my head is spinning thanks guys !
P.S. Did i answer my own post # 11 ?